The present invention is directed to apparatuses for adjusting light assemblies. More particularly, the present invention is directed to apparatuses for adjusting lamp assemblies mounted to towers on lighting systems.
Mobile lighting systems are used extensively to provide the necessary light for outdoor and other work sites that lack adequate ambient lighting. Conventional mobile lighting systems often comprise an extendable light tower and an electrical power generator mounted to a trailer. The extendable light tower can be raised to provide the desired illumination once the trailer has been properly positioned at a work site. Typically, the extendable light tower will be rotatably mounted to the trailer so that the lights can be aimed in different directions by rotating the tower relative to the trailer. A rotatable tower allows for changing the horizontal direction of all the lights as a unit; however, it does not allow for each light on the tower to be individually adjusted. To provide proper illumination at a work site, it is often necessary to aim the lights toward a desired area by changing the horizontal and/or vertical direction of some or all of the lights individually. The process of aiming the lights can be difficult and time-consuming.
Many conventional mobile lighting systems allow for adjusting the horizontal and vertical direction of the individual lights to aim the lights. Typically these conventional systems have one or more fasteners that can be manually loosened to permit rotation of the mounting bracket and/or lamp. In these systems, the fasteners, often nuts and bolts, are the same fasteners that secure the lamp to the mounting bracket and secure the mounting bracket to the support member.
Lighting systems that require the securing fasteners to be loosened in order to rotate one of the lamps or mounting brackets have several disadvantages. First, the operator must remember to fully retighten the fasteners after adjustment to prevent them from becoming loose during transport. If the fasteners become loose during transport, there is a chance that the lamp could be damaged. Second, if the fasteners include a nut with nylon (e.g., Nylock nuts and nuts with lock washers), the holding capacity of the nut may degrade each time that it is loosened and retightened. Third, the edges of the fasteners frequently become worn over time because operators sometimes use pliers to tighten and loosen these fasteners instead of the appropriately sized wrench. Fourth, many fasteners require tools, such as wrenches to tighten them. Requiring external tools to adjust fasteners is an inconvenience and sometimes, when tools are not available, prevents proper adjustment of the lights. Some mobile lighting systems attempt to provide tool-less adjustment mechanisms, but often these alternatives have many of the same problems described above.
Many conventional mobile lightening systems have a rotatable tower that permits the lights on the tower to be adjusted as a unit from the ground. Many of these systems have a knob connected to a threaded rod tightened into the tower collar to lock the tower into position. These knob assemblies, however, have several problems. Unless the knob is extremely tight, the wind can cause the tower to rotate. Conversely, if the knob is over-tightened, an operator might not be able to loosen it to rotate the tower. Moreover, the threaded rods are sometimes bent due to overtightening and the threads on the rod are susceptible to becoming gummed up with debris. Bent rods and gummed-up threads are difficult, if not impossible, to tighten. Additionally, some knob assemblies use plastic knobs, which tend to break over time.
The present invention is directed to light adjustment apparatuses and methods for adjusting light assemblies. In one embodiment of the invention, the apparatus includes a light holder having a housing, a mounting bracket coupled to the housing, a support member and an engagement member. The support member is rotatably attached to the mounting bracket so that the light holder and the mounting bracket can be rotated as a unit about an axis of rotation. The support member or the mounting member has a plurality of locking apertures forming a curve, and the other has at least one receiving aperture. The engagement member is releasably disposed at least partially within one of the locking apertures and the receiving aperture to restrict the mounting bracket from rotating relative to the support member about the axis of rotation.
In another embodiment of the invention, a method of adjusting a light assembly includes removing an engagement member from a first aperture in a mounting bracket and a second aperture in a support member, and rotating the mounting bracket and a light assembly attached to the mounting bracket as a unit so that the light is aimed at a selected orientation. The method further includes aligning a third aperture in the mounting bracket with the second aperture in the support member, and placing the engagement member in the third aperture of the mounting bracket and the second aperture of the support member.